Polo mints are good for your horse.
My horse likes grey fruit
Nicker makers!! You can get them at tractor supply! We have a GIANT bag of them!
Honestly I just use balancer pellets from my horses daily ration. Work great for clicker training/rewarding and I know they're good for him!
Horse treatery, stud muffins, squeezy buns, paddock cakes, mrs. pastures
Those little bit size treats they come in apple or carrots.